Power lawn mower including shortened control arms for use in deck lift system

ABSTRACT

A self-propelled power lawn mower having a deck lift system for raising and lowering the cutter deck assembly together with the engine deck and engine as a single unit to adjust the cutting height of the mower. Control arms are short enough length so that pivoting of the control arms an angle Φ of fifteen degrees during raising or lowering of the cutter deck assembly causes the cutter deck assembly to move a vertical distance “d” of no more than about 2.5 inches.

This application is a continuation-in-part (CIP) of U.S. Ser. No.09/412,589, filed Oct. 5, 1999 now U.S. Pat. No. 6,205,753, thedisclosure of which is hereby incorporated herein by reference.

Known commercial power mowers are generally divided into three separatecategories: self-propelled walk-behind mowers, ride-on mowers operatedby a seated occupant, and stand-on mowers operated by a standingoccupant.

For example, U.S. Pat. No. 4,920,733 discloses a typical walk-behindpower mower. U.S. Pat. No. 5,865,020 discloses a typical ride-on mowerwhere an operator sits on a seat during mower operation. U.S. Pat. Nos.5,984,031, 5,964,082 and 5,507,138 disclose known stand-on mowers, eachof these three patents hereby being incorporated herein by reference.

Deck lift systems for power mowers are also known in the art. Forexample, see the cutter deck lift system in U.S. Pat. No. 5,865,020, thedisclosure of which is incorporated herein by reference. The mower orcutter deck is supported by a plurality of chains and a deck lift systemenables the cutter deck to be raised and lowered in order to adjust thecutting height of the mower. Control arms (e.g., see reference numeral40 in the '020 patent) are utilized to control the lateral position orlocation of the cutter deck. Unfortunately, the control arms in the '020patent are rather long. Long control arms are needed in the '020 systembecause the engine deck (upon which the engine is mounted behind theseat) does not move up/down along with the cutter deck during cuttingheight adjustment (i.e., the engine and engine deck remain fixed inplace). Thus, the control arms are lengthy in order to reduce the amountof lateral movement of the cutter deck during raising/loweringoperations in order to prevent large amounts of slack and/or tightnessfrom building up in the pulley belt(s) which extend between the enginedrive shaft and the blade pulleys mounted in top of the cutter deck.Unfortunately, long control arms means that the mower is moresusceptible to damage caused by sideloads (e.g., when the side of thecutter deck is hit by something, or runs into an object such as a curbor tree).

Accordingly, it will be apparent to those skilled in the art that thereexists a need in the art for a power mower deck lift system that can bedesigned so as to enable the efficient use of short control arms withoutovercomplicating the design of the mower. It is an object of thisinvention to fulfill this and other needs which will become apparent tothe skilled artisan from reading the instant disclosure.

SUMMARY OF THE INVENTION

An object of this invention is to provide a deck lift system on a mowerwherein control arms can be made short in length so as to make the mowermore resistant to damage caused by sideload impact(s) on the cutterdeck.

Another object of this invention is to provide a deck lift system on amower wherein the cutter and engine deck assemblies (including theengine) are raised and lowered together as one unit when adjusting theblade cutting height of the mower.

Another object of this invention is to provide a power mower where theoperator is capable of standing or sitting during different modes ofmower operation.

Another object of this invention is to provide a mower where thebattery(ies) can be located between feet of an operator in order tolower the overall center of gravity of the mower.

Another object of this invention is to provide a mower designed so thatwhen going up a hill a mower operator can move from a sitting positionto a standing position so that the overall center of gravity of themower can be moved forward to minimize potential for tipping backward.

Another object of this invention is to provide a seat assembly whichenables an operator to easily jump off of or abandon the machine.

Another object of this invention is to provide a seat on a mower, wherethe seat may be folded up into a storage or stowed position when theoperator is standing on the mower or when there is a desire to transportor store the mower.

Another object of this invention is to provide a mower including a seatstructure which is both comfortable and may be efficiently moved betweendeployed and non-deployed positions.

Another object of this invention is to provide a deck lift system whichlifts an engine deck and a cutter deck together with one another, sothat control arms utilized for positioning the deck can be designed tobe shorter thereby enabling the deck assembly to be more resistant tonegative impacts which may be caused by sideloads.

Yet another object of this invention is to satisfy or fulfill one ormore of the above listed_(objects).

Certain embodiments of this invention fulfill one or more of theabove-listed needs and/or objects by providing a self-propelled powerlawn mower comprising:

first and second rear drive wheels that are independently driveable soas to enable the mower to conduct approximate zero radius turns about azero radius turning axis;

a foot platform for supporting at least one foot of an operator of themower, said foot platform being located at an elevation less than anelevation of a top edge of at least one of said rear drive wheels;

a deck lift system for raising and lowering a cutter deck assembly, anengine deck, and an engine together as one unit in order to adjust ablade cutting height of the mower;

control arms pivotally attached to at least one of the cutter deck andengine deck in order to maintain lateral positioning of the cutter deckassembly and engine deck during the raising and lowering; and

wherein said control arms are short enough in length so that pivoting ofthe control arms an angle Φ of fifteen (15) degrees either upward ordownward during raising or lowering of the cutter deck assembly causesthe cutter deck assembly to move a vertical distance “d” no more thanabout 2.5 inches.

Certain embodiments of this invention further fulfill one or more of theabove-listed needs and/or objects by providing a self-propelled powerlawn mower comprising:

at least one drive wheel;

a cutter deck assembly;

an engine;

a deck lift system for raising and lowering the cutter deck assembly andengine together in order to adjust a blade cutting height of the mower;and

pivoting control arms for helping maintain lateral positioning of thecutter deck assembly and engine during the raising and lowering.

IN THE DRAWINGS

FIG. 1 is a side elevation view of a zero radius turning self-propelledpower lawn mower according to a first embodiment of this invention, themower including both standing and sitting modes and this Figure showingthe operator in a sitting position.

FIG. 2 is a side elevational view of the power mower of FIG. 1, showingthe operator in a standing position on a foot platform.

FIG. 3 is a side elevational view of the power mower of FIGS. 1-2,without an operator and showing the seat in a folded-up or stowedposition.

FIG. 4 is a side elevational view of the power mower of FIGS. 1-3,showing an operator getting on or off of the mower, wherein the seat ispivoted about a pivot as the operator moves forward or rearward.

FIG. 5 is a side elevational view of a zero radius turningself-propelled power mower according to a second embodiment of thisinvention, the mower including both standing and sitting modes and thisFigure showing the operator in a sitting position.

FIG. 6 is a side elevation view of the mower of FIG. 5, showing the seatfolded up absent an operator.

FIG. 7 is a side elevation view of a zero radius turning self-propelledpower mower according to a third embodiment of this invention, the mowerincluding both standing and sitting modes, as well as control cables;this Figure showing the operator in a sitting position.

FIG. 8 is a rear elevational view of the mower of FIGS. 1-4, absent anoperator.

FIG. 9 is a perspective view of a zero radius turning self-propelledpower mower according to a fourth embodiment of this invention, themower including both standing and sitting modes; this figureillustrating the seat in a deployed position.

FIG. 10 is a perspective view of the power mower of FIG. 9, againillustrating the seat in a deployed position.

FIG. 11 is a side elevation view of the mower of FIG. 9-10, showing theseat in a deployed position.

FIG. 12 is a top view of the mower of FIGS. 9-11.

FIG. 13 is a rear elevation view of the mower of FIGS. 9-12.

FIG. 14 is a perspective view of the seat assembly or structure of themower of FIGS. 9-13.

FIG. 15 is a side view of certain elements of the seat structure of themower of FIGS. 9-14, illustrating the seat in a deployed position.

FIG. 16 is a side view of certain elements of the seat structure of themower of FIGS. 9-15, showing the seat in a folded-up or non-deployed(i.e., stowed) position.

FIG. 17 is a perspective view of the seat structure attached to thetractor frame of the mower of FIGS. 9-16.

FIG. 18 is a perspective view illustrating the seat structure attachedto the tractor frame of the mower of FIGS. 9-17.

FIG. 19 is a perspective view of the tractor frame of the mower of FIGS.9-18.

FIG. 20 is another perspective view of the tractor frame of the mower ofFIGS. 9-19.

FIG. 21 is a side plan view of certain components of the mower of FIGS.9-20, specifically illustrating the control arms which function toposition the cutter and engine decks as they are moved upward and/ordownward by the deck lift system (e.g., this figure shows the rear ofthe engine deck over top of the toe area of the operator).

FIG. 22 is an exploded perspective view of an exemplary control arm ofthe mower of FIGS. 9-21.

FIG. 23 is a perspective view from above and behind, illustrating thecutter deck assembly with blade drive pulleys thereon, of the mower ofFIGS. 9-22.

FIG. 24 is a close up perspective view of a portion of the cutter deckassembly of FIG. 23.

FIG. 25 is a top view illustrating a clutch and pulley system used inconjunction with the cutter deck assembly of FIGS. 23-24.

FIG. 26 is a schematic side view illustrating a control arm and itspivot ranges as it extends from the tractor frame according to onepossible embodiment for use in conjunction with the FIGS. 9-25embodiment of this invention.

FIG. 27 is a schematic side view illustrating a control arm and itspivot ranges as it extends from the tractor frame according to anotherpossible embodiment for use in conjunction with the FIGS. 9-25embodiment of this invention.

FIG. 28 is a side cross sectional view of a portion of the cutter deckassembly of FIGS. 23-24.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THIS INVENTION

Referring now more particularly to the accompanying drawings in whichlike reference numerals indicate like parts throughout the severalviews.

FIGS. 1-4 and 8 illustrate a zero radius turning self-propelled powerlawn mower according to a first embodiment of this invention. Operator41 of the mower may use the mower either when sitting down on the seator alternatively when standing up on the foot platform. In otheralternative embodiments of this invention, the mower may be usedprimarily as a sit-down mower, or primarily as a stand-on mower.

Referring to FIGS. 1-4 and 8, the lawn mower includes: operator seat 1for the operator to sit on during mower operation; seat pivot axis 2about which seat 1 pivots or rotates; spring(s) or shock absorber(s) 3for dampening the front of the seat for operator comfort; seat supportor frame 4; wheelie roller(s) 5; pivot axis 6 for enabling seat support4 to fold up along with the seat; spring(s) or shock absorber(s) 7 fordampening the rear of the seat for operator comfort; upwardly extendingspaced apart and parallel supports or frames 8 provided between theoperator's legs for supporting seat support 4 and for housing battery 30or tools therebetween; stationary or pivotable foot platform 9 on whichthe operator may stand during mower operation; latch 10 for preventingseat 1 from folding up unexpectedly; engine frame weldment 11 connectedto cutter or mower deck assembly 12 within which the cutting blades areprovided; frame 13 for suspending or supporting cutter deck assembly 12and/or engine frame weldment 11; engine deck 31 defining a plane uponwhich a pair of hydraulic or hydrostatic pumps 22 and the engine aremounted; a pair of laterally spaced side plates 14 extending upwardlyfrom engine deck 31 or frame in order to support (directly orindirectly) at least (1) normally stationary handlebar 32, (2) a pair ofspaced apart pivotable front handle grips 33 and a pair of spaced apartrear handle grips 34 (see U.S. Pat. No. 5,809,755, incorporated hereinby reference), (3) hydraulic oil tank 35, (4) a pair of spaced apart armrests 17 which may be padded, (5) a pair of arm rest support brackets15, (6) corresponding arm rests pivots 16 for enabling the arm rests tofold up out of the way so that a standing operator can stand on eitherside of the platform without substantial interference from an arm rest,(7) pivot stop 18 for arm rest supports 15 to come to rest against whenin a deployed position so as to support the arm rests, and (8) dashboardor console 36 including an hour gage (not shown); a pair of frontcasters or wheels 37 supported by frame 13 or alternatively by thecutter deck assembly 12; combustion engine 38 mounted on the plane ofengine deck 31; engine shaft 39 extending from the engine downwardlythrough an aperture in the engine deck 31 for driving the cutter bladesvia belts and pulleys 40; operator 41 who may operate the mower eitherwhile seating on seat 1 as shown in FIG. 1 or when standing on platform9 as shown in FIG. 2; control arms 42 which enable cutter deck 12 andengine deck 31 to move up and down relative to frame 13 and dampenmovement therebetween; a pair of independently drivable rear drivewheels 43 which rotate about a common rear drive wheel axis 44; andright and left hand hydrostatically controlled rear drive wheel motors45 (see FIG. 8) whose wheel driving direction and speed are controlledby pumps 22 via pivoting handle controls 33 and/or 34 as described inU.S. Pat. No. 5,809,755 which is incorporated herein by reference.

In certain embodiments of this invention, engine 38 is moved forwardrelative to certain conventional mowers so that drive shaft 39 thereofis located forward ol the front edge of rear drive wheels 43 and alsoforward of the front edge of supports 14. Moreover, in certainembodiments, the entire engine 38 is located forward of the front edgeof rear drive wheels 43. This forward positioning of the engine permitsadditional weight to be provided closer to the front of the mower inorder to offset weight distributed by the operator when on seat 1.

The location, function, and structure of platform 9, hydro pumps 22, andwheel motors may be as shown and/or described in any of U.S. Pat. Nos.5,765,357 or 5,809,755, both of which are hereby incorporated herein byreference.

Still referring to FIGS. 1-4 and 8, the left rear drive wheel may bedriven in a forward direction by one motor 45 while simultaneously theright rear drive wheel is driven in a rearward direction by the othermotor 45 at approximately the same speed so that the mower conducts anapproximate zero radius turn about a vertical zero radius turning axis65 that is spaced equal distance between the rear wheels 43 and extendsupwardly through common rear wheel axis 44. Left hand pump 22 is influid communication with the left wheel motor 45 so that the drivedirection and speed of left drive wheel 43 are controlled by pivotingleft hand controls or levers 33 and 34; while right hand pump 22 is influid communication with right wheel motor 45 so that the drivedirection and speed of right drive wheel 43 are controlled by pivotingright hand controls or levers 33 and 34. The right and left rear drivewheels 43 are thus controlled independently from one another in certainembodiments of this invention. Each rear drive wheel is preferablymounted on its own drive axle, and the axle of one wheel 43 may be partof the corresponding wheel motor 45 or alternatively may be separatefrom the motor. The same is true for the axle of the other rear drivewheel 43. In alternative non-zero radius turning embodiments, both reardrive wheels may be mounted on a single supporting axle.

In zero radius turning embodiments herein, at least a portion of footplatform 9 may be positioned so that the operator when standing on theplatform is substantially uneffected by centrifugal force during zeroradius turns of the mower. In certain embodiments, platform 9 may bepositioned so that it is intersected by zero radius turning axis 65. Inother embodiments, platform 9 is positioned relative to handle grips32-34 so that the operator when standing on platform 9 and gripping aportion of the handle control assembly is substantially uneffected bycentrifugal force created during approximate zero radius turns of themower and at least a portion of his or her body may be on or near (e.g.,within six inches of) the vertical turning axis 65. In certainembodiments, handle grips 32-34 are located forward of the verticalturning axis 65 and the platform rearward thereof so that the operatorwhen standing on platform 9 is substantially uneffected by centrifugalforce created during zero radius turns of the mower. In any of the aboveembodiments, at least a portion (or in some embodiments a substantialportion such as a thigh, head, torso, shoulder, chest, stomach, or thelike) of the standing operator's body may be substantially at or nearthe vertical zero radius turning axis 65 during mower operations such asturning, going up hills, or during flat terrain operation.

In certain zero radius turning embodiments, hydrostatic pumps 22 are inconventional communication with hydrostatic motors 45 by way of, forexample, a plurality of hydraulic fluid hoses (not shown) disposedbetween each pump and corresponding mower. Pumps 22 including knownswash plates (not shown) generate hydraulic fluid pressure which istranslated through one of two hoses connecting each pump 22 to acorresponding motor 45. The hydraulic hoses are coupled between eachpump 22 and its motor 45 so as to allow hydraulic fluid to flow in bothdirections between each pump and its motor. One hydraulic hose may beprovided for allowing hydraulic fluid to flow in one direction andanother hose for permitting the fluid to flow in the opposite directionbetween a motor 45 and its corresponding pump 22. Each pump 22 includesa conventional pump control lever (not shown) extending therefrom forpermitting the standing or sitting operator to control the speed andforward/reverse sense of each rear drive wheel via a hand lever(s)33-34. Hydraulic pumps 22 may be driven by engine 38 via belts or anyother suitable means. Alternatively, rear drive wheels 43 could insteadbe driven by chains or gears in a known manner, or by any other suitablevariable speed devices.

Still referring to FIGS. 1-4 and 8, seat 1 may include an approximatelyupright section 1 a as well as an approximately horizontal section 1 b,so that seat 1 may be approximately L-shaped. The operator sits onportion 1 b and may lean backwards against section 1 a. As illustrated,seat 1 in certain embodiments is positioned entirely behind the zeroradius turning axis 65 which extends upwardly through horizontal wheelaxis 44. However, grip portions 32-34 of the handle control assembly maybe located forward of axis 65 so that at least a portion of theoperator's body can be on or near this turning axis 65 during sittingand/or standing operation of the mower. As shown in this particularembodiment, when in their deployed positions arm rests 17 are locatedbehind vertical turning axis 65. However, in other embodiments arm rests17 may be located on or forward of axis 65 depending on the preferenceof the operator or mower designer.

When the operator operates the mower when sitting on seat 1, the centerof gravity of the combination of mower and operator is further rearwardthan when the operator is standing on platform 9. This is because theplatform is located forward of the seat (preferably, a substantialportion of the platform is located forward of the front edge of theseat).

Seat 1 is designed so that seat portion 1 b is elongated in forwardand/or rearward directions. Therefore, the operator can adjust theposition of his/her weight on the seat at various positions therebycausing the mower's center of gravity to move forward and/or rearwardduring operation. For example, the operator may sit on the middle ofseat 1 during operation of the mower on flat terrain. However, whengoing down a hill, the operator may slide further back on seat 1 inorder to put as much weight as possible on the rear drive wheels 43 toincrease traction on the rear tires by offsetting front end weight whengoing down a hill. When mowing up hills, the operator may move from asitting position to a standing position on platform 9 and lean forwardover the handle control assembly in order to put additional weight onthe front of the mower thereby reducing the potential of tippingrearwardly when going up hills. Alternatively, when going up a hill theoperator may simply slide or move forward on the seat 1.

Springs or shock absorbers 3 and 7 are optionally associated with seat 1and are provided for operator comfort during sitting modes. At least onespring or other biasing means 3 is positioned proximate and below afront portion of seat 1 to dampen vibration or movement of the front ofthe seat during mower operation. Spring(s) 3 is generally oriented in avertical manner with its biasing axis being approximately vertical withrespect to flat ground on which the mower travels. Meanwhile, at leastone spring or other biasing means 7 is provided for dampening movementof a rear portion of seat 1. Spring 7 is oriented at an angle θ of fromabout 20°-90° (most preferably from about 30°-60°) relative to thevertical and thus relative to the axis of spring 3. Seat 1 is mounted onseat support 4. Support 4 and seat 1 may rotate or pivot together aboutfixed axis 6. Thus, when substantial weight is placed on the rearportion of seat 1, the seat together with support 4 tend to rotate in acounterclockwise direction as defined in FIG. 2 about axis 6. Spring(s)7 biases support 4 and thus seat 1 against too much counterclockwisetendency, thereby dampening vibration felt by the operator during seatedoperation of the mower.

Seat 1 may be folded up in certain embodiments in order to shorten thelength of the mower for transport and/or storage (or for the operator tooperate the mower when standing). For example, seat 1 may be folded upfrom its deployed position (see FIGS. 1-2) to a non-deployed or stowedposition (see FIG. 3). To do this, seat 1 together with support 4 is/arerotated clockwise about fixed pivot axis 6 from the FIG. 1-2 position tothe folded-up FIG. 3 position (i.e., to the stowed position). Inpreferred embodiments, pivot axis 6 is positioned forward of the rearedge of rear drive wheels 43 but rearward of common horizontal wheelaxis 44 so that the seat assembly when folded upwardly provides for amore compact mower. Optionally, pivot latch 10 may be provided so thatthe seat assembly cannot be folded up unexpectedly. Alternatively, nopivot latch 10 need be provided in certain embodiments.

Optionally, an operator presence control (OPC) switch may be associatedwith platform 9 in certain embodiments of this invention. Such an OPCswitch may cause the mower and/or blades to turn off when the operatorleaves or steps off of the platform in certain embodiments. An exemplaryOPC switch associated with the platform is disclosed and described inU.S. Pat. No. 5,809,755, incorporated herein by reference.Alternatively, in other embodiments, a similar OPC switch may beassociated with the handle control assembly so that the mower engineand/or blades shut off if and when the operator's hands are removed fromthe handle control assembly during operation. It is preferred that themower not be equipped with a single OPC switch associated with only theseat, due to the need for potential standing operation during certainconditions (although, in certain alternative embodiments an OPC switchassociated only with the seat may be utilized).

The seat assembly of the mower of FIGS. 1-4 and 8 is designed so that itis easy for an operator 41 to get off of or onto the mower. FIG. 4illustrates an operator either getting onto or off of the mower byallowing seat 1 to pivot about axis 2 as the operator moves eitherforward or rearward. For example, assuming that the operator 41 isgetting on the mower as shown in FIG. 4, operator 41 straddles portion 1a of the seat with his/her legs, and as the operator moves forwardhe/she contacts and pushes downward on portion 1 b of the seat so thatas the operator sits down the seat 1 rotates clockwise about pivot axis2 until it reaches the FIG. 1-2 position. Thus, the operator does nothave to crawl over an entire seat assembly in order to get on the mower.Such a pivoting seat is optional and need not be provided in allembodiments of this invention.

Still referring to FIG. 4, when an operator 41 desires to get off of themower from a seated position, the operator 41 may simply push his/herback rearwardly against the top of section 1 a of the seat therebycausing the seat to rotate counterclockwise about pivot axis 2 into itsFIG. 4 position as the operator rearwardly leaves the mower. Thisenables the operator to get off of the mower without having to crawlover top of a fixed seat assembly.

As shown in FIG. 4, approximately horizontal pivot axis 2 may bepositioned at an elevation at or above the surface of seat section 1 band axis 6 during normal mower operation (see FIGS. 1-2). Such apositioning of axis 2 makes it less likely for seat 1 to be pivotedcounterclockwise about axis 2 unintentionally or accidentally. It isalso noted that the two optional arm rests 17 are supported andconnected to side supports 14 (instead of the seat) so that the armrests need not interfere with an operator getting on or off of themower. In alternative embodiments, the optional arm rests may besupported by the seat itself or any other suitable structure.

The first and second laterally spaced side supports 14 are attached toand extend upwardly from the plane of engine deck 31. In suchembodiments, control rods operatively connected to pivoting levers 33-34may be utilized and extend between the levers and corresponding pumps 22in order to control rear drive wheel direction and/or speed.

FIG. 7 illustrates another embodiment of this invention, wherein firstand second elongated flexible control cables 61 replace theabove-described control rods. First and second similar cables 61 extendbetween levers 33-34 and the corresponding pumps 22, thereby allowingpivoting movement of levers 33-34 to control the speed and/or drivedirection of rear drive wheels 43. Cables 61 are preferred in the FIG. 7embodiment, because the elevation of the engine deck 31, cutter deckassembly 12, and pumps 22 is/are adjustable upwardly and downwardlyrelative to the height of the handle control assembly 32-34. This isbecause the engine deck upon which engine 38 and pumps 22 are mounted issuspended from frame 13 and is adjustable upwardly and downwardly alongwith cutter deck 12 relative to the frame 13 in order to adjust thecutting height of the mower. In the FIG. 7 embodiment, no arm rests areprovided.

Cables 61 of the FIG. 7 embodiment are push/pull type cables which actsimilar to flexible rods and are resistant to buckling. When cables 61are pushed forward or downward by forward pivoting of lever 34 and/orlever 33, this causes a pushing force to be applied to pump 22 in adirection going toward the rear of the mower as shown in FIG. 7. Cables61 are preferred when the handle control assembly is mounted at anelevation independent from and variable relative to the height of theengine deck 31 and pumps 22. However, cables 61 need not be utilized inall such embodiments.

FIGS. 5-6 illustrate a self-propelled zero radius turning moweraccording to yet another embodiment of this invention. The FIGS. 5-6embodiment differs from the FIGS. 1-4 and 8 embodiment in that in FIGS.5-6 the seat 1 is generally flat and does not have a back portion. FIG.5 illustrates seat 1 in a deployed position with the operator sitting onthe mower. FIG. 6 illustrates seat 1 in a folded up position or stowedposition, with seat 1 and support 4 having been rotated clockwise aboutpivot axis 6. In certain embodiments herein, pad or cushion 71 may bemounted on a rear surface or edge of side supports 14 so as to cushionthe knees of the operator against banging into supports 14 during ridingand/or sitting operation of the mower, and/or to provide a rest upagainst which seat 1 can contact in a stowed position.

FIGS. 9-25 illustrate a zero radius turning self-propelled power lawnmower according to a fourth embodiment of this invention. This mowerincludes first and second hydro pumps for controlling first and secondcorresponding wheel motors, so that the first and second rear drivewheels 43 may be driven independently in order to conduct zero radiusturns as discussed above. Referring to FIGS. 9-13, the mower includes:independently drivable rear drive wheels 43; cutter deck assembly 12below which the cutting blades cut grass; front caster wheels 37; footplatform 9; seat 1; gas tank supports 80 for supporting respective gastanks; battery housing structure 81 for housing a battery 30 and whichalso functions to help support the seat assembly; steering controllevers 32 and 34 which enable the rear drive wheels 43 to beindependently drivable in opposite directions at the same time so as toenable the mower to perform zero radius turns about a vertical zeroradius turning axis 65; vertically extending support plates 14 whichsupport console 36 and handle grips 32-34; and deck lift lever 82 whichenables the cutter deck assembly 12 together with the engine deck 31 tobe raised and lowered together in order to adjust the height of themower cut.

For example, when deck lift lever 82 is pulled upwardly, the cutter deckassembly 12 together with the engine deck 31 (and engine) is raised soas increase the height of the mower cut. Chain linkage 83 suspends thedeck assembly 12 and 31 and enables it to be raised and lowered inaccordance with the position of lever 82.

Further regarding the deck lift system, in the embodiment of FIGS. 9-13,21, 22, and 26-27, when deck lift lever 82 is pulled upwardly in aclockwise pivoting fashion (“clockwise” as defined from the port side ofthe mower as in FIGS. 10 and 11) by an operator, this causes a rod 99(see FIG. 12) traversing the mower frame to also rotate in a clockwisedirection. This rod, attached to deck lift rods 100 on either side ofthe mower, causes rods 100 to be pulled toward the rear of the mower sothat lift brackets pivot counterclockwise about pivot axes 101 in orderto lift the cutter deck assembly 12 together with the engine deck 31 andengine upwardly via chains 83 in order to raise the cut of the mower. Ina similar manner, when lever 82 is lowered from a locked position, theweight of the deck assemblies and engine causes brackets 100 to rotateclockwise (“clockwise” as defined in, for example, FIG. 11) about axes101 and rods 100 to move in a forward direction so that the cutter deckassembly 12 is lowered along with the engine deck 31 and engine. In thisrespect, control arms 130 (best shown in operation in FIG. 21) maintainthe lateral position of the cutter deck assembly 12 and engine deck 31(and the engine) during lower/raising by the deck lift system. As can beseen in FIG. 21, control arms 30 in this embodiment are much short thanthose in the '020 patent, so that mowers according to certainembodiments of this invention are better able to withstand sideloadsapplied to the deck assemblies.

Battery(ies) 30 (e.g., a DC battery) supplies electric power to mowercomponents such as electric starting systems, optional lights, etc. Asshown in FIGS. 13-16, at least a portion of battery 30 is located at anelevation below an elevation of a rotational axis (e.g., see 44 inFIG. 1) of one or both rear drive wheels 43, so as to lower the overallcenter of gravity of the mower. Moreover, in certain embodiments of thisinvention, the vertically oriented zero radius turning axis mayintersect the batter due to its advantageous location. Because battery30 and battery housing 81 are located on or above the foot platform 9 asshown in FIGS. 9, 10, 12-18, respective foot areas for respective feetof the operator are provided on opposite sides of the battery housing 81on platform 9. Thus, battery 30 is preferably at least partially locatedbetween feet (or feet areas) of the operator during normal moweroperation regardless of whether the operator is operating the mower in astanding mode while standing upright on platform 9 or operating themower in a sitting mode while sitting on seat 1 with feet still on theplatform 9 on opposite sides of the battery 30 (feet of the moweroperator fit on the platform 9 on opposites sides of the battery 30 in asimilar manner as shown in FIGS. 1, 2, 5 and 7).

Referring in particular to FIGS. 14-18, the seat assembly of this moweris unique and has several improvements relative to conventional seatassemblies. In particular, the seat assembly structure according to thisfourth embodiment of this invention includes: seat 1; rear seat pivot102; seat adjustment frame 103 including a pair of approximatelyparallel sidewalls connected by a cross member for enabling the seat 1to be moved forward/rearward via slots 105; front seat spring 104 foroperator comfort; front seat pivot 106 which enables the seat assemblyto pivot between deployed and stowed positions; seat adjustment releaselever 107; upper seat support frame member 108 including a pair ofapproximately parallel sidewalls 108 a and 108 b connected by crossmember 108 c; spring bolt 109 which extends through and along an axis ofrear seat spring 110; lower seat support frame member 111 including aspring receiving surface 111 a, a pair of approximately parallelsidewalls 111 b and 111 c, and a cross member 111 a/111 d connecting thesidewalls 111 b and 111 c; slots 112 for enabling frame 111 to moveupward/downward so as to adjust the vertical position of seat 1; batteryhousing structure 81 including battery box rear wall 113, battery boxbottom wall 121, battery box front wall 122, and pivoting battery boxlid or top wall 124 which pivots at 124 a (preferably, battery boxsidewalls 115 are approximately parallel to another, as are the top wall124 and the bottom wall 121 of the battery box); and finally tractorframe structure 114. Spring 104 is located under a front portion of seat1 and the other spring 110 is located at least partially between seatsupports 108 and 111. Preferably, support frames 108 and 111 areconnected (the word “connected” herein means either directly connectedor indirectly connected) to one another via pivot 106. Moreover, supportframe 111 is connected to either the tractor frame or a deck structurevia slots 112 with bolts therethrough so that the position of the seatassembly may be selectively adjusted.

In certain embodiments, foot platform 9 extends underneath of batterybox 81 and defines a bottom wall thereof for supporting the batterythereon. Alternatively, the battery box 81 itself may include a bottomwall for supporting the battery 30 that is separate and distinct fromthe foot platform 9 upon which the operator may stand or rest his/herfeet.

Tractor frame structure 114 includes (e.g., see FIGS. 14 and 17-20):tractor frame left sidewall 114 a, tractor frame right sidewall 114 b,tractor frame rear cross bar 116 connecting the two tractor framesidewalls at respective rear edges thereof, battery box sidewalls 115,battery box rear wall 113, battery box bottom wall 121, battery boxfront wall 122, tractor frame cross member 123 for extending between andconnecting/supporting the sidewalls, and control arm support tabs 131.Preferably, tractor frame sidewalls 114 a and 114 b are approximatelyparallel (i.e., parallel plus/minus 10 degrees in either direction) toone another, and cross member 123 is approximately perpendicular to thetractor frame sidewalls.

As best shown in FIGS. 12-13, the unique shape and structure of tractorframe 114 enables wheel motors 45 which drive the respective rear drivewheels to be mounted to the respective exterior surfaces of the tractorframe sidewalls 114 a and 114 b. Wheel motors 45 are preferably mountedto the tractor frame 114 because the engine deck 31 and cutter deckassembly 12 move up/down selectively due to the deck lift system (i.e.,it is not desirable to have the wheel motors moving up/down relative tothe wheels/tires themselves). As shown in FIGS. 19-20, wheel motors (WM)45 may be mounted to the exterior surfaces of the respective tractorframe sidewalls 114 a and 114 b at positions “WM.” The parallelsidewalls of the tractor frames provide an excellent mounting positionfor the wheel motors 45. This also means that the rear drive wheels 43are mounted to sidewalls 114 a and 114 b and are supported thereby(instead of to the engine deck as in certain conventional mowers).Additionally, the hydro pumps may be mounted on a top surface of thetractor frame 114 or alternatively may be mounted on the engine deck 31.

As shown best in FIGS. 19 and 21, cross member or front wall 123 of thetractor frame is shaped so as to include approximately parallel portions123 a and 123 b that are connected by angled portion 123 c. Intermediateangled portion 123 c forms an angle of from about 30-85 degrees withportion 123 b, and an angle of from about 30-85 degrees with portion 123a. As shown in FIG. 21, the presence of angled portion 123 c enablesportions 123 a and 123 b to be approximately parallel to one another yetoffset from one another thereby creating space 123 d above angledportion 123 c where the rear edge of engine deck 31 can move up and downduring cutting height adjustment initiated by the deck lift system. Inother words, the presence of angled portion 123 creates space 123 d sothat the space above the toes of the operator (the toes would be at area123 e) may be used for enabling the engine deck to move up/down.

Referring to FIGS. 14-17, seat 1 is selectively movable between adeployed position and a stowed or non-deployed position. Seat 1 isillustrated in a deployed position in FIGS. 14 and 15, and in a stowedor non-deployed (i.e., folded up) position in FIG. 16. In FIG. 17 andFIG. 18, the seat 1 is halfway between the two positions and is in theprocess of either being deployed or stowed.

In order to move seat 1 from its deployed position (FIGS. 14-15) to itsstowed position (FIG. 16), the seat 1 along with seat adjustment frame103, upper seat support ID frame member 108, and springs 104, 110 arepivoted forward (i.e., in a counterclockwise direction as defined inFIG. 15) about pivot axis 106 until the seat 1 reaches its stowed ornon-deployed position as shown in FIG. 16. Likewise, in order to moveseat 1 from its stowed position (see FIG. 16) to its deployed position(see FIGS. 14-15), seat 1 along with seat adjustment frame 103, upperseat support frame member 108, and springs 104 and 110 are pivotedclockwise about front seat pivot axis 106 until the pivoting movement isstopped by the bottom of spring 110 contacting surface 111 a so that theseat thus reaches its deployed position as shown in FIGS. 14-15. As canbe seen, springs 104 and 110 are connected to members 103 and 108,respectively, and thus move along with the seat 1 when the seat pivotsbetween deployed and stowed positions.

As can be seen in FIGS. 14-17, seat 1 along with frame 108 pivot aboutaxis 106 over a range of at least 45 degrees, more preferably at leastabout 60 degrees, to enable the seat to move from a deployed to a stowedposition, or vice versa (even more preferably from about 70-120 degrees,and most preferably from about 75-100 degrees). This rather high degreeof angular pivoting movement is enabled by the efficient and compactnature of the seat assembly. It is stressed that the particulars of theseat assembly shown in FIGS. 14-17 are for purposes of example only, andare not intended to be limiting; in other words, other types of seatstructures consistent with one or more teachings herein may also be usedin other embodiments of this invention.

As can be seen, front seat spring 104 and rear seat spring 110 areprovided for operator comfort and function in a shock absorbing mannerwhen the mower is being operated. Additionally, rear seat spring 110(which is attached to upper seat support frame 108, and not to lowerseat support frame 111) prevents seat 1 and support frame member 108from pivoting too far rearwardly in the clockwise direction about pivotaxis 106 (i.e., “clockwise” pivoting is defined as viewed in FIG. 15).In other words, when seat 1 is being moved from a stowed position to adeployed position, the bottom of spring 110 eventually hits the springcontacting surface 111 a of support frame member 111 thereby stoppingthe clockwise movement of seat 1 and frame member 108 about axis 106 inorder to define the deployed position for seat 1. In certain exemplaryembodiments, surface 111 a includes an aperture defined therein forreceiving an end or head of bolt 109 when spring 110 comes to rest onsurface 111 a (as the seat goes down, the head of the bolt goes throughthe aperture but the washer and spring do not go through the aperture;the washer is between the bolt head and the spring end). Additionally,bolt 109 may be adjusted in order to both selectively change the biasingforce provided by spring 110 and/or to adjust the angle at which seat 1is normally located absent an operator.

As can be seen in FIGS. 14-18, seat 1 folds upwardly (toward its stowedposition) and downwardly (toward its deployed position) about fixed axis106, without the need for any pins to be pulled or the like. Springs 104and 110 are positioned so that the entire seat unit (seat 1 along withsprings 104 and 110, and frame members 103 and 108) pivots about axis106 in a unitary manner. Additionally, the location of pivot axis 106 islocated far enough rearwardly on the mower so that seat 1 is preventedfrom hitting supports 114 when pivoted to its stowed position (althoughthe seat may come to rest up against same in the stowed position incertain embodiments of this invention). Moreover, pivot axis 106 islocated at an elevation high enough so that the seat structure includingseat 1 and frame members 103 and 108 can be made to have a low enoughprofile such that the mower does not prevent the seat from being movedbetween stowed and deployed positions. Pivot 106 is forward enough toenable the overall mower length to be rather short, but back far enoughfor the seat to clear the handle assembly. In this regard, pivot axis106 is preferably located at an elevation greater than that of footplatform 9 and at an elevation also greater than that of top battery boxwall 124. In most preferred embodiments, fixed pivot axis 106 is locatedat an elevation greater than the elevation of the rotational axis of therear drive wheels 43, although it may be located lower than same incertain embodiments. Additionally, fixed seat pivot axis 106 ispreferably located rearwardly of the rear drive wheel axis (of one orboth rear drive wheels 43) and optionally may also be located rearwardlyof the rear edge of foot platform 9.

As shown in FIG. 15, springs 104 and 110 have respective axes which areapproximately parallel to one another both in deployed and stowedpositions. In this regard, the respective axes of springs 104 and 110define an angle with respect to one another of from about 0 to 15degrees as viewed from the side as in FIG. 15, more preferably of fromabout 0 to 8 degrees. This approximately parallel alignment of the axesof springs 104 and 110 has been found to provide for a more comfortableride for the seated operator and for an efficient seat assembly system.Additionally, while only a single spring 104 and a single spring 110 areshown in FIGS. 14-18, it will be recognized by those skilled in the artthat additional springs may be provided.

Pivots 102 and 106 are approximately parallel to one another, and mayenable the seat to pivot in opposite directions. As for rear seat pivot102, it enables seat 1 to pivot in directions 90 about axis 102. Thus,pivot axis 102 functions to enable spring 104 to cushion the ride of anoperator seated on seat 1 especially in the forward direction when theoperator is leaning forward on the seat 1. In preferred embodiments,rear seat pivot axis 102 is located at an elevation above front pivotaxis 106, and is also located rearwardly of both axis 106 and rearwardlyof the rear edge of rear drive wheels 43 (although this need not be thecase in all embodiments of this invention).

The position of seat 1 may also be adjusted upwardly and downwardly viaslots 112, as well as forwardly/rearwardly via slots 105. The selectiveadjustability of seat 1 is advantageous in that the seat assembly maymore easily accommodate operators of different sizes.

The positioning of battery 30 in box or housing 81 at a location atleast partially below an axis of at least one of the rear drive wheelsenables a lower center of gravity of the mower thereby enabling safemower operation. The lower the center of gravity, the less likely themower is to tip when travelling on hills or the like. Moreover,positioning of battery 30 between the feet of the operator aboveplatform 9 utilizes space which otherwise may not have been used. Thislocation of the battery also enables it to be positioned furtherrearwardly than would otherwise have been permitted thereby achievingthe result of moving the center of gravity of the mower furtherrearwardly in order to provide for smoother and more efficient moweroperation.

Yet another advantage associated with the seat structure shown in FIGS.14-18 is that the operator can operate the mower in a standing mode(i.e., the operator stands upright on platform 9) regardless of whetherseat 1 is in a deployed position (FIGS. 14-15) or in a stowed ornon-deployed position (FIG. 16). Thus, the operator may easily lift upoff of the seat when going up hills and quickly sit back down ifdesired. Alternatively, if the operator desires to operate the mower ina standing mode for an extended period of time, the operator can stowthe seat as shown in FIG. 16 and thereafter operate the mower whilestanding on platform 9. The low profile of the seat and compact natureof the seat assembly as illustrated in FIGS. 14-18 enables the seatassembly to be small enough so that it does not interfere with operationof the mower by a standing operator regardless of whether the seat 1 isdeployed or not.

Another unique feature associated with the fourth embodiment of thisinvention relates to control arms 130 and is best illustrated in FIGS.21-22 and 26-27. It is again noted that cutter deck assembly 12 isrigidly affixed to engine deck 31 (with the engine thereon) so that thetwo deck assemblies may be raised and lowered together as one unitarystructure by the deck lift system of this mower (e.g., as initiated bydeck lift lever 82). End 92 of each control arm 130 is pivotallyconnected to the cutter deck assembly 12 while the other end 93 of eachcontrol arm is pivotally connected to the tractor frame structure 114 atpivot axis 91 (e.g., see FIGS. 21-22). Control arms 130 function tomaintain the desired lateral position of deck assemblies 12, 31throughout their range of movement. In this regard, control arms 130 arepivotally connected to, and extend between, both cutter deck assembly 12on the one hand and tractor frame 114 on the other hand. Thus, when deckassemblies 12 and 31 are raised by the deck lift system, control arms130 pivot upwardly about axis 91 in direction “A” (see FIG. 26). Axis 91is defined by the apertures or holes provided in control arm supporttabs 131. In a similar manner, when the deck assemblies 12, 31 arelowered by the deck lift system, control arms 130 pivot downwardly indirection “B” (i.e., counterclockwise as shown in FIG. 21) about pivotaxis 91.

As shown in FIGS. 26-27, control arms 130 may be of different lengths indifferent embodiments of this invention. However, in both the FIG. 26and the FIG. 27 embodiments, control arms 130 are significantly shorterthan conventional control arms. In particular, with regard to FIG. 26,control arms 130 according to this invention are preferably short enoughso that they must pivot at least about 29° (see the angle Φ in FIG. 26)about axis 91 in order to move the cutter deck assembly upwardly ordownwardly over a vertical distance “d” of five (5) inches. Preferably,in order to move the cutter deck assembly 12 (and thus also the enginedeck and engine) up or down five inches, the control arms 130 accordingto this invention preferably are pivoted about axis 91 from about27-80°, more preferably from about 30-60°, and most preferably fromabout 30-50° (theses are the full range of movement for the control arms130 for cutting positions of the cutter deck and corresponding blades).In other embodiments of this invention, pivoting of the control arms 130fifteen (15) degrees about axis 91 causes the cutter deck assembly 12 tomove either vertically upward or vertically downward no more than about2.5 inches, and more preferably no more than about 2.0 inches and mostpreferably no more than about 1.8 inches (these vertical distances “d”are measured irrespective of how much the deck may move laterallyforward or rearward during the lift due to the pivoting of arms 130about axis 91).

The shorter control arms 130 of this invention enable a more compact andefficient mower. Moreover, the shorter control arms enable the mower towithstand additional sideload (e.g., when deck assembly 112 is impactedfrom the side). The longer the arms, the more adverse the effects ofsideload. Shorter control arms are enabled in accordance with theinstant invention because the cutter deck assembly 12 is rigidlyconnected to the engine deck 31 and the two deck assemblies moveupwardly and downwardly together in order to adjust the cut height ofthe mower. Conventional deck lift systems typically require longercontrol arms because the cutter deck assembly is separate from theengine and the two do not move upwardly and downwardly together duringdeck lift operations. Thus, because conventional mowers have enginesseparate from the cutter deck, it is undesirable to have tosignificantly compensate the belt drive system for significant back andforth lateral movement which accompanies large angular pivotingmovements of control arms. Because our engine deck and engine is movedalong with the cutter deck assembly, the instant invention can afford tohave the deck assemblies move laterally rearward/forward along withup/down movement and thus can accommodate shorter control arms 130because the belt drive system between the engine drive shaft and thecutter blades is not changed (i.e., the distance between the two remainsapproximately constant) during deck lifting/lowering operations.

FIG. 22 is an exploded view of a control arm which may be utilized inconjunction with this invention. Control arm 130 includes adjustable rodend 130 a (ball socket), nut 130 b for locking rod end 130 a frommovement (i.e., to prevent wear), control arm weldment 130 c, shockabsorber rubber (e.g., neoprene) bushings 130 d, and spanner pipe ortube 130 e which extends through bushings 130 d and the elongatedtubular section of control arm weldment 130 c.

Yet another unique aspect of this fourth embodiment of this invention isbest illustrated in FIGS. 23-25 and 28. In particular, an angled sectionat 12 a of the cutter deck assembly 12 between lobes 12 b and 12 c iscut out or removed and covered up by a fill or plug plate 141. Thecorner defined by 95 and 140 that is removed at area 12 a enables theheight or profile of the cutter deck assembly at that location to bereduced. The lower profile of the cutter deck assembly at the locationof plate 141 enables more room for the engine clutch which extendsdownwardly from a position above plate 141 (e.g., see FIGS. 25 and 28).Clutch 142 is illustrated from above in FIG. 25.

The cutter deck includes top deck surface 95 which defines the plane ofthe cutter deck, as well as deck sidewall 140 which extends generallydownward from top surface 95. FIG. 28 is a cross-sectional view of thecutter deck assembly 12 taken along the center of plate 141 of FIG. 23.Referring in particular to FIG. 28, plate 141 covers the cutout or holein the cutter deck by extending between and connecting cutter decksidewall 140 with cutter deck top surface 95. Welds 96 or any othersuitable means may be utilized to secure plate 141 to the cutter deck inthis regard. Plate 141 preferably defines an angle Ω of from about 15-75degrees with top surface 95 of the cutter deck, more preferably of fromabout 25-65 degrees, and most preferably an angle Ω of from about 35-55degrees. Plate 141 is located at the rear center edge of the cutter deckbetween lobes 12 b and 12 c. Again, this enables clutch 142 as shown inFIGS. 25 and 28 to be located at a lower elevation than would otherwisebe possible. The provision of plate 141 (as opposed to a right angleconnection between cutter deck members 95 and 140) also enables easierinstallation/removable of clutch 142 and the blade belt driven by theclutch. By enabling the clutch and thus the engine to be located at alower elevation, a lower center of gravity of the mower is possible.

Once give the above disclosure, many other features, modifications, andimprovements will become apparent to the skilled artisan. Such otherfeatures, modifications, and improvements are therefore considered to bea part of this invention, the scope of which is to be determined by thefollowing claims.

What is claimed is:
 1. A self-propelled power lawn mower comprising:first and second rear drive wheels that are independently driveable soas to enable the mower to conduct approximate zero radius turns about azero radius turning axis; a foot platform for supporting at least onefoot of an operator of the mower, said foot platform being located at anelevation less than an elevation of a top edge of at least one of saidrear drive wheels; a deck lift system for raising and lowering a cutterdeck assembly, an engine deck, and an engine together as one unit inorder to adjust a blade cutting height of the mower; control armspivotally attached to at least one of the cutter deck and engine deck inorder to provide lateral positioning of the cutter deck assembly andengine deck during the raising and lowering; and wherein said controlarms are short enough in length so that pivoting of the control arms anangle Φ of fifteen (15) degrees either upward or downward during raisingor lowering of the cutter deck assembly causes the cutter deck assemblyto move a vertical distance “d” no more than about 2.5 inches.
 2. Themower of claim 1, wherein said control arms are short enough in lengthso that pivoting of the control arms an angle Φ of fifteen (15) degreeseither upward or downward during raising or lowering of the cutter deckassembly causes the cutter deck assembly to move a vertical distance “d”no more than about 2.0 inches.
 3. The mower of claim 2, wherein saidcontrol arms are short enough in length so that pivoting of the controlarms an angle Φ of fifteen (15) degrees either upward or downward duringraising or lowering of the cutter deck assembly causes the cutter deckassembly to move a vertical distance “d” no more than about 1.8 inches.4. The mower of claim 1, wherein a pivot axis about which the controlarms pivot is defined by apertures in control arm support tabs providedon a tractor frame structure.
 5. The mower of claim 4, wherein thecontrol arms are pivotally connected between said cutter deck assemblyand a tractor frame structure, so that a first end of each control armis pivotally connected to the tractor frame structure and a second endof each control arm is pivotally connected to the cutter deck assembly.6. The mower of claim 5, wherein the control arms are pivotallyconnected to a front wall of the tractor frame structure via control armsupport tabs, each of said control arm support tabs being rigidlyaffixed to the tractor frame structure and having an aperture definedtherein for defining a pivot axis of the corresponding control arm. 7.The mower of claim 1, wherein said engine deck is rigidly affixed tosaid cutter deck assembly so that a plane defined by said engine deckupon which the engine is mounted is at an elevation above an elevationdefined by a top surface of said cutter deck.
 8. The mower of claim 1,wherein a rear edge of said engine deck extends over top of, andrearwardly of, rearwardmost ends of said control arms.
 9. A power mowercomprising: at least one drive wheel; an engine deck structure uponwhich an engine is mounted; a cutter deck assembly for housing one ormore cutting blades for cutting grass; a deck lift system for raisingand lowering the cutter deck assembly, the engine deck, and the enginetogether as a unit in order to adjust a blade cutting height of themower; and wherein a control arm, for helping provide lateralpositioning of the cutter deck assembly during the raising and lowering,is short enough in length so that pivoting of the control arm an angle Φof fifteen (15) degrees during raising or lowering of the cutter deckassembly causes the cutter deck assembly to move a vertical distance “d”of no more than about 2.5 inches.
 10. The mower of claim 9, wherein saidcontrol arm is short enough in length so that pivoting of the controlarm an angle Φ of fifteen (15) degrees during raising or lowering of thecutter deck assembly causes the cutter deck assembly to move a verticaldistance “d” no more than about 2.0 inches.
 11. The mower of claim 9,wherein said control arm is short enough in length so that pivoting ofthe control arm an angle Φ of fifteen (15) degrees either upward ordownward during raising or lowering of the cutter deck assembly causesthe cutter deck assembly to move a vertical distance “d” no more thanabout 1.8 inches.
 12. The mower of claim 9, wherein a pivot axis aboutwhich the control arm pivots is defined by apertures in control armsupport tabs provided on a tractor frame structure.
 13. The power mowerof claim 9, wherein a first end of the control arm is pivotally attachedto the cutter deck assembly and a second end of the control arm ispivotally attached to a tractor frame structure.
 14. The power mower ofclaim 13, wherein the tractor frame structure supports each of a footplatform and a seat for an operator.